Reduction of Epoxidized Vegetable Oils: A Novel Method to Prepare Bio‐Based Polyols for Polyurethanes

A novel method, epoxidation/reduction of vegetable oils, is developed to prepare bio‐based polyols for the manufacture of polyurethanes (PUs). These polyols are synthesized from castor oil (CO), epoxidized soybean oil, and epoxidized linseed oil and their molecular structures are characterized. They are used to prepare a variety of PUs, and their thermomechanical properties are compared to those of PU made with petroleum‐based polyol (P‐450). It is shown that PUs made with polyols from soybean and linseed oil exhibit higher glass transition temperatures, tensile strength, and Young's modulus and PU made with polyol from CO exhibits higher elongation at break and toughness than PU made with P‐450. However, PU made with P‐450 displays better thermal resistance because of tri‐ester structure and terminal functional groups. The method provides a versatile way to prepare bio‐polyols from vegetable oils, and it is expected to partially or completely replace petroleum‐based polyols in PUs manufacture.

     

Development of wood protective polyurethane coatings from mahua oil-based polyetheramide polyol: a renewable approach

The present work reports the preparation of wood protective polyurethane (PU) from mahua oil-based polyetheramide polyol and its performance evaluation. The synthesis of polyetheramide polyol was carried out in two steps: the first step deals with the synthesis of mahua oil fatty amide (MFA) from mahua oil by base catalyzed aminolysis reaction and the second step deals with the synthesis of polyetheramide polyol from diglycidyl ether of bisphenol-A (DGEBA) and MFA. The structure of the synthesized polyetheramide polyol was confirmed by the Attenuated total reflection fourier transform infrared (ATR-FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopy. The synthesized polyetheramide polyol was used as a precursor for the wood protective PU coatings. The performance of the prepared wood protective PU coatings was evaluated by the measurements of the various performance properties. The results reveal that mechanical, thermal, and microbial properties of the prepared PUs are satisfactory compared to other literature reported vegetable oil-based PUs; whereas, water, solvent, and chemical resistance of the prepared PUs are quite good. The study concludes that mahua oil-based polyetheramide polyol is a suitable precursor for the preparation of wood protective PU.     

Novel long chain unsaturated diisocyanate from fatty acid: Synthesis,characterization, and application in bio‐based polyurethane

A novel long chain linear unsaturated terminal diisocyanate, 1,16‐diisocyanatohexadec‐8‐ene (HDEDI) was synthesized from oleic acid via Curtius rearrangement. Its chemical structure was identified by FTIR, ¹H NMR, ¹³C NMR, and HRMS. This diisocyanate was used as a starting material for the preparation of entirely bio‐based polyurethanes (PUs) by reacting it with canola diol and canola polyol, respectively. The physical properties and crystalline structure of the PUs prepared from this diisocyanate were compared to their counterparts prepared from similar fatty acid‐derived diisocyanate, 1,7‐heptamethylene diisocyanate (HPMDI). The HDEDI based PUs demonstrated various different properties compared to those of HPMDI based PUs. For example, HDEDI based PUs exhibited a triclinic crystal form; whereas HPMDI based PUs exhibited a hexagonal crystal lattice. In addition, canola polyol‐HDEDI PU demonstrated a higher tensile strength at break than that of canola polyol‐HPMDI, attributed to the higher degree of hydrogen bonding associated with the former sample. Nevertheless, lower Young's modulus and higher elongation in canola polyol‐HDEDI PU were obtained because of the flexibility of the long chain introduced by the HDEDI diisocyanate. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3302–3310, 2010     

Novel conductive nanocomposites from perfluoropolyether waterborne polyurethanes and carbon nanotubes

The exceptional electrical conductivity of carbon nanotubes (CNTs) has been exploited for the preparation of conductive nanocomposites based on a large variety of insulating polymers. Among these, perfluoropolyether‐polyurethanes (PFPE‐PUs) represent a class of highly performing fluorinated materials with excellent water/oil repellency, chemical resistance, and substrate adhesion. The incorporation of highly conductive fillers to this class of highly performing materials allows them to be exploited in new technological and industrial fields where their unique properties need to be combined with the electrical conductivity or the electrostatic dissipation properties of carbon nanotubes. However, no studies have been presented so far on nanocomposites based on PFPE‐PUs and CNTs. In this work, polymer nanocomposites based on waterborne PFPE‐PUs and increasing amounts of carboxylated multiwall CNTs (COOH‐CNTs) were prepared and characterized for the first time. The effect of increasing concentration of COOH‐CNTs on the physical, mechanical, and surface properties of the nanocomposites was investigated by means of rheological measurements, dynamic mechanical analysis, thermal characterization, optical contact angle measurements, and scanning electron microscopy. In addition, electrical measurements showed that the highly insulating undoped PFPE‐PU system undergoes substantial modifications upon addition of COOH‐CNTs, leading to the formation of conductive nanocomposites with electrical conductivities as high as 1 S/cm. The results of this study demonstrate that the addition of COOH‐CNTs to PFPE‐PU systems represents a promising strategy to expand their possible use to technological applications where chemical stability, water/oil repellence and electrical conductivity are simultaneously required. Copyright © 2014 John Wiley & Sons, Ltd.     

Thermal analysis of soybean oil based polyols

Soybean oil based polyols (5-OH polyol, 10-OH polyol and 15-OH polyol) were synthetised from epoxidized soybean oil. The melting peak of polyols and the relationship between melting peak and the number-average functionality of hydroxyl in polyols were investigated by differential scanning calorimetry (DSC). The thermal decomposition of polyols and some of their thermal properties by thermogravimetry (TG) and derivative thermogravimetry (DTG) were also studied. The thermal stability of polyols in a nitrogen atmosphere was very close hence they had a same baseplate of triglyceride for polyols. The extrapolated onset temperature of polyols in their thermal mass loss, first step had a decreasing order: 5-OH polyol>10-OH polyol>15-OH polyol due to the difficulty in forming multiple elements ring of them had the same order. The thermal behavior of polyols under non-isothermal conditions using Friedman’s differential isoconversional method with different heating rates indicated that the 5-OH polyol had the lowest activation energy in thermal decomposition amongst these polyols according to the same fractional mass loss because of the weakest intramolecular oligomerization. The 15-OH polyol was prior to reach the mass loss region because the six-member ring is more stable than the three-member ring from 10-OH polyol and more easily formed.     

Efficacy of clay content and microstructure of curing agents on the structure–property relationship of new‐generation polyurethane nanocomposites

The physicomechanical properties of new polyurethanes (PUs) derived from toluene diisocyanate, poly(propylene glycol), and cured by third‐generation hyperbranched polyester polyol (HB3), trimethylolpropane (TMP), or glycerol and their nanocomposites have been investigated. An apparent microphase‐segregated morphology of PU nanocomposites cured by HB3 has been observed by transmission electron microscopy and atomic force microscopy. Morphological studies reveal regions of mostly exfoliated and some intercalated morphology in the case of the nanocomposites, which have been further ascertained by X‐ray diffraction analysis. The HB3‐cured PU nanocomposite containing 8 wt% of modified montmorillonite (Cloisite 30B) clay shows approximately 140% increase in tensile strength along with improvement in thermal and dynamic mechanical properties in comparison with the control hyperbranched PU. It has also been found from Fourier transform infrared spectroscopy analysis that the extent of tethering reactions between the polymer chains carrying residual –NCO groups and the reactive hydroxyl (?OH) groups of HB3 is significant, and the nanofiller has been found to preferentially react with the –NCO group of the prepolymer. Furthermore, the properties of HB3‐cured PU have been compared with the glycerol and TMP‐cured PUs and their nanocomposites. The physicomechanical and thermal properties for nanocomposites of HB3‐cured PUs are superior to those of the conventionally cured PUs. Copyright © 2011 John Wiley & Sons, Ltd.     

Effect of polyol structure on the properties of the resultant magnetic polyurethane elastomer nanocomposites

In this study, two types of magnetic polyurethane (PU) elastomer nanocomposites using polycaprolactone (PCL) and polytetramethylene glycol (PTMG) as polyols were synthesized by incorporating thiodiglycolic acid surface modified Fe₃O₄ nanoparticles (TSM‐Fe₃O₄) into PU matrices through in situ polymerization method. TSM‐Fe₃O₄ nanoparticles were prepared using in situ coprecipitation method in alkali media and were characterized by X‐ray diffraction, Fourier Transform Infrared Spectrophotometer, Transmission Electron Microscopy, and Vibrating Sample Magnetometer. The effects of PCL and PTMG polyols on the properties of the resultant PUs were studied. The morphology and dispersion of the nanoparticles in the magnetic nanocomposites were studied by Scanning Electron Microscope. It was observed that dispersion of nanoparticles in PTMG‐based magnetic nanocomposite was better than PCL‐based magnetic nanocomposite. Furthermore, the effect of polyol structure on thermal and mechanical properties of nanocomposite was investigated by Thermogravimetric Analysis and Dynamic Mechanical Thermal Analysis. A decrease in the thermal stability of magnetic nanocomposites was found compared to pure PUs. Furthermore, DMTA results showed that increase in glass transition temperature of PTMG‐based magnetic nanocomposite is higher than PCL‐based magnetic nanocomposite, which is attributed to better dispersion of TSM‐Fe₃O₄ nanoparticles in PTMG‐based PU matrix. Additionally, magnetic nanocomposites exhibited a lower level of hydrophilicity compared to pure PUs. These observations were attributed to the hydrophobic behavior of TSM‐Fe₃O₄ nanoparticles. Moreover, study of fibroblast cells interaction with magnetic nanocomposites showed that the products can be a good candidate for biomedical application. Copyright © 2013 John Wiley & Sons, Ltd.     

Poly(urethane‐co‐benzoxazine)s via reaction of phenol terminated urethane prepolymers and benzoxazine monomer and investigation of their properties

In the present work, a new method was developed for the combination of polyurethanes (PUs) and polybenzoxazine (PBz) to obtain novel thermoset poly(urethane‐co‐benzoxazine)s with good thermal, mechanical, and electrical properties as well as low temperature curing profile. Knowing the catalytic effect of compounds possessing free phenolic groups on ring opening polymerization of benzoxazine monomers, preparation of phenol terminated urethane oligomers (PTPU) as the macroinitiator for a benzoxazine monomer (Ba) was considered. Firstly, NCO‐terminated urethane prepolymers were prepared from the reaction of poly(tetramethyleneether glycol), and 2,4‐tolylene diisocyanate, and then end functionalized with bisphenol‐A under proper condition. DSC, DMTA, and gel content measurements were applied to find optimum ring opening polymerization condition (170°C for 1 hr and 200°C for 15 min). Various kinds of thermoset polymers were prepared by the reaction of PTPU at different molecular weights with variable contents of Ba. All of monomeric and polymeric materials were characterized by conventional spectroscopic methods and their thermal, mechanical, viscoelastic, and electrical properties were measured and properties were correlated to their structure. Due to the interesting properties of these new materials, the possibility of using them as electrical insulators with higher service temperature in comparison to common PUs were examined and their potential applicability was confirmed. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis,characterization, and molecular modeling studies of novel polyurethanes based on 2,2′‐[ethane‐1,2‐diylbis(nitrilomethylylidene)]diphenol and 2,2′‐[hexane‐1,6‐diylbis(nitrilomethylylidene)] diphenol hard segments

Novel polyurethanes (PUs) based on 2,2′‐[ethane‐1,2‐diylbis(nitrilomethylylidene)]diphenol and 2,2′‐[hexane‐1,6‐diylbis(nitrilomethylylidene)]diphenol as hard segments containing four aromatic diisocyanates (4,4′‐diphenylmethane diisocyanate, toluene 2,4‐diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate) have been prepared. Fourier transform infrared, UV spectrophotometry, fluorescence spectroscopy, ¹H NMR and ¹³C NMR spectroscopy, thermogravimetric analysis, and differential thermal analysis have been used to determine the structural characterization and thermal properties of the segmented PUs. All the PUs contain domains of both semicrystalline and amorphous structures, as indicated by X‐ray diffraction. The acoustic properties have been calculated with the group contribution method. Molecular dynamics simulations have been performed on all the PUs to estimate the cohesive energy density and solubility parameter values, which compare well with the values calculated with the group contribution method. Furthermore, the simulation protocols have been applied to the PUs to produce X‐ray diffraction plots to determine the phase morphology of the PUs. The surface properties of the PUs have been estimated from the simulation protocols. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6032–6046, 2006     

Lipidic polyols using thiol‐ene/yne strategy for crosslinked polyurethanes

Oleic acid and α,ω‐diacid were converted into propargylic esters followed by thiol‐ene/yne coupling (TEC/TYC) functionalization in presence of mercaptoethanol. The multiradical addition on fatty esters leads to the formation of lipidic polyols (OH1 and OH2), as judged by ¹H NMR and mass spectroscopies as well as by size exclusion chromatography. The crosslinking reaction between TEC/TYC‐based polyols and 4,4′‐methylene bis(phenylisocyanate) isocyanate reactant was monitored by FTIR experiment and reaction parameters were optimized. By differential scanning calorimetry, relatively high glass transitions are measured corresponding to structure with little or without dangling chain. Moreover, the thermal stability of the resulting plant oil‐based polyurethane materials (PU1 and PU2) were found to be fully consistent with that of other lipidic PUs respecting a three‐step process. Thanks to TYC methodology, fatty α,ω‐diacid produces lipidic polyol without dangling chain and lipidic thermoset PU with relatively high T_g. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1597–1606     

Investigation of thermal,mechanical, and electrical properties of novel polyurethanes/high molecular weight polybenzoxazine blends

In order to prepare tough polyurethane (PU) electrical insulator with improved thermal stability and electrical insulating properties, high molecular weight polybenzoxazine precursor was mixed and co‐cured with crosslinkable urethane prepolymers. Polybenzoxazine precursor (Bmda) was synthesized from reaction of bisphenol‐A, methylenedianiline, and paraformaldehyde. Epoxy‐terminated polyurethanes (EPU1‐4) were prepared by the reaction of glycidol with NCO‐terminated urethane oligomers. The oligomers were prepared from different molecular weight versions of polycaprolactone polyol (CAPA) and hexamethylene diisocyanate. Blends were prepared through thermal treatment of equal weights of two precursors dissolved in chloroform. Optimum curing condition was determined by DSC and DMTA analysis and measurement of the gel content for cured samples. Viscoelastic, thermal, mechanical, and electrical properties of cured samples were investigated and structure–property relationship was established. Copyright © 2008 John Wiley & Sons, Ltd.     

Polyisobutylene‐based polyurethanes: VII. structure/property investigations for medical applications

The outstanding hydrolytic and oxidative stabilities of polyisobutylene‐based polyurethanes (PIB‐based PUs) were reported earlier. Herein, we summarize recent investigations aimed at further enhancing hydrolytic‐oxidative stabilities (in terms of resistance to aqueous buffer, nitric acid and CoCl₂/H₂O₂) together with excellent mechanical properties. The purity and dryness of ingredients together with precise NCO/OH stoichiometry (～1.05) are essential to obtain PIB‐based PUs with improved properties. Static and dynamic mechanical properties were optimized by analyzing stress–strain traces, thermal (TGA, DSC) responses, self‐organization (XRD) profiles, and rheological (DMA, creep) information. According to microstructure and surface analyses (AFM, contact angle) annealing increases the segregation of individual segments and increases surface hydrophobicity, which in turn enhances the shielding of hydrolytically oxidatively vulnerable carbamate bonds by inert PIB barriers, and thus significantly improves hydrolytic‐oxidative stability. Annealing does not much affect bulk properties, such as static and dynamic mechanical and thermal properties; however, it increases damping over a wide temperature range. Annealed PIB‐based PU containing 72.5% PIB exhibits outstanding hydrolytic‐oxidative stability together with ～26 MPa tensile strength, ～500% elongation, and ～77 Microshore hardness. PIB‐based PUs are significantly more resistant to hydrolytic and oxidative degradation than ElastEon? E2A, a commercially available PDMS‐based PU, widely used for medical applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 532–543     

Polyurethanes with separately tunable biodegradation behavior and mechanical properties for tissue engineering

Two series (random and block) poly(glycolide‐co‐ε‐caprolactone) macrodiols with various glycolide to ε‐caprolactone ratios (50/50 and 30/70, R‐PG50C, R‐PG30C, B‐PG50C, and B‐PG30C) were synthesized. Next, segmented polyurethanes (PUs) were synthesized based on the synthesized macrodiols, 1,6‐hexamethylene diisocyanate and 1,4‐butanediol (PU‐R30, PU‐R50, PU‐B30, and PU‐B50). Effect of glycolide (G) and ε‐caprolactone (C) monomers arrangement (random or block) on the PUs properties were investigated via FTIR, ¹H NMR, DSC, TGA, DMA, SEM, and mechanical tests. All PUs illustrated T_g (−33°C to −48°C) and T_m (102°C to 139°C) corresponding to the soft and the hard segments, respectively. Polymers based on block macrodiols also showed T_m related to the soft segments. While PUs underwent a two‐step thermal degradation, the PUs based on block macrodiols indicated higher degradation temperature. Dynamic mechanical analysis results evidenced development of a well‐defined microphase separated structure in PU‐R30. Contact angle (about 70°‐80°) and water uptake (around 20% after 24 hours) of the PU films are close to those suitable for tissue engineering materials. The PU based on R‐PG30C (PU‐R30) exhibited the highest tensile strength (2.87 MPa) followed by PU‐B50 and PU‐R50. Over a 63‐day in vitro degradation study in phosphate buffered saline, the PUs showed variable weight loss (up to 40%) depending on their soft segments composition and arrangement. Also, the PUs showed no cytotoxicity. Thus, these PUs with tunable biodegradation rate and mechanical properties are suitable candidates for tissue engineering.     

Diaminobisbenzothiazole chain extended polyurethanes as a novel class of thermoplastic polyurethane elastomers with improved thermal stability and electrical insulation properties

This work was devoted to the development of a new class of modified polyurethane as an electrical insulating material. For this purpose, NCO‐terminated urethane prepolymers at different NCO contents were prepared and chain extended by 6,6′‐oxybis(2‐aminobenzothiazole) (ABT) to produce thermoplastic polyurethane elastomers. All of the polymers were characterized by FTIR and ¹HNMR spectroscopies and examined for their thermal, mechanical, and electrical properties. The dynamic mechanical measurements results showed two glass transitions indicating phase separation. A considerable improvement in the thermal and electrical properties in comparison to common polyurethanes was detected for these polymers. The level of enhancement in the measured properties was related to the polyol molecular weight, hard segment content, and consequently the amount of the introduced urea and benzothiazole moieties. These findings indicated the improved high service temperature performance of these materials as electrical insulator for metallic surfaces. Copyright © 2008 John Wiley & Sons, Ltd.     

Polyisobutylene‐based polyurethanes. VI. Unprecedented combination of mechanical properties and oxidative/hydrolytic stability by H‐bond acceptor chain extenders

We describe the design, synthesis, characterization, and testing of novel polyurethanes (PUs) exhibiting unprecedented combinations of outstanding mechanical properties and oxidative/hydrolytic stabilities. This achievement is due to the use of polyisobutylene (PIB) soft segments plus flexible H‐bond acceptor chain extenders (HACEs): the PIB imparts superior oxidative/hydrolytic stability and the HACE produces reinforcing H‐bonds, which lead to outstanding mechanicals. Oxidative/hydrolytic stability was quantitated by retention of tensile strength and elongation after exposure to nitric acid. PUs containing 60–70% PIB retain their mechanical properties, whereas Carbothane®, Bionate®, and Elast‐Eon?, PUs marketed for chemical stability, degrade severely under the same conditions. Various HACEs were identified (e.g., hexaethylene glycol, tripropylene glycol, tributylene glycol, 3,3′‐diamino‐N‐methyl‐dipropylamine, etc.) and their effect on mechanical properties was investigated. A PIB‐ and HACE‐containing PU exhibited 29.2 MPa tensile strength, 620% elongation, and 80 Shore A hardness. Properties were analyzed in terms of stress–strain profiles, differential scanning calorimetry traces, dynamic mechanical thermal analysis plots, and oxidative/hydrolytic stability. The properties of various PIB‐based rubbers, that is, thermoplastic PUs, SIBSTAR®, and thermoset butyl rubber are compared. The novel PUs are promising candidates for biomaterials and industrial applications where a combination of mechanical properties and oxidative/hydrolytic stability is of the essence. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2361–2371, 2010     

Effect of structure on properties of polyols and polyurethanes based on different vegetable oils

We synthesized six polyurethane networks from 4,4′‐diphenylmethane diisocyanate and polyols based on midoleic sunflower, canola, soybean, sunflower, corn, and linseed oils. The differences in network structures reflected differences in the composition of fatty acids and number of functional groups in vegetable oils and resulting polyols. The number average molecular weights of polyols were between 1120 and 1300 and the functionality varied from 3.0 for the midoleic sunflower polyol to 5.2 for the linseed polyol. The functionality of the other four polyols was around 3.5. Canola, corn, soybean, and sunflower oils gave polyurethane resins of similar crosslinking density and similar glass transitions and mechanical properties despite somewhat different distribution of fatty acids. Linseed oil–based polyurethane had higher crosslinking density and higher mechanical properties, whereas midoleic sunflower oil gave softer polyurethanes characterized by lower T_g and lower strength but higher elongation at break. It appears that the differences in properties of polyurethane networks resulted primarily from different crosslinking densities and less from the position of reactive sites in the fatty acids. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 809–819, 2004     

Liquid crystalline properties of unsegmented and segmented polyurethanes synthesised from high aspect ratio mesogenic diols

A series of novel tetrad high aspect ratio mesogenic diol monomers 4-{[4-(n-hydroxyalkoxy)-phenylimino]-methyl}-benzoic acid 4-{[4-(n-hydroxyalkoxy)-phenylimino]-methyl}-phenyl ester were prepared with varying alkoxy spacer length (n=2,4,6,8,10) by reacting 4-formylbenzoic acid 4-formylphenyl ester and 4-(n-hydroxyalkoxy) anilines. Two series of thermotropic main chain liquid crystalline unsegmented polyurethanes (PUs) were obtained by the polyaddition of the mesogenic diols with hexamethylene diisocyanate (HMDI) and methylene bis(cyclohexylisocyanate) (H₁₂MDI) in dimethylformamide respectively. The effect of the incorporation of a third component namely polyol on the liquid crystalline properties of the polyurethanes was also studied. Linear segmented PUs were synthesised by a two-step block copolymerisation method. The PUs synthesised were based on six spacer mesogenic diol chain extender, soft segments poly(tetramethylene oxide)glycol (PTMG) (M_n= 650,1000,2000) and polycaprolactone diol (PCL) (M_n=530,1250,2000) of varying molecular weights and different diisocyanates including HMDI, H₁₂MDI and methylene bis(phenylene isocyanate) (MDI). Structural elucidation was carried out by elemental analysis, fourier transform infra red (FT-IR), nuclear magnetic resonance (¹H NMR and ¹³C NMR) spectroscopy. Inherent viscosity of the unsegmented polymers measured in methanesulphonic acid at 26°C was in the range of 0.13 - 0.65 dL/g while the molecular weights and molecular weight distribution of the segmented polyruethanes was determined using gel permeation chromatography (GPC). Mesomorphic properties were studied by differential scanning calorimetry (DSC) and hot stage polarising optical microscopy and the thermal stability was determined by thermogravimetric(TG)analysis. The monomeric diols and the polyurethanes exhibited nematic texture and good mesophase stability. It was observed that the partial replacement of the mesogenic diol by the polyol of varying molecular weights influenced the phase transitions and the occurrence of mesophase textures. The phase transition temperatures of the investigated polyurethanes showed dependence on the chain length of the soft segment and on the content of the mesogen moiety. A higher content of mesogenic moiety was needed to obtain liquid crystalline property when the soft segment length was increased as observed in the case of PTMG. Grained and threaded textures were observed depending on the molecular weight of the soft segment, the mesogen content and the diisocyanate. The stress-strain analyses showed that the polymers bused on high molecular weight PTMG soft segment have elastomeric property while the PCL based PUs displayed no elastomeric property.     

A green approach toward oleic‐ and undecylenic acid‐derived polyurethanes

Naturally occurring oleic and undecylenic acids were used as raw materials for the synthesis of novel polyurethanes (PUs). The application of environmentally friendly thiol‐ene additions to 10‐undecenoate and oleate derivatives was studied with the goal of obtaining renewable diols. The resulting monomers were then polymerized with 4,4′‐methylenebis (phenylisocyanate), in N,N‐dimethylformamide solution using tin (II) 2‐ethylhexanoate as catalyst, to produce the corresponding thermoplastic PUs (TPUs). Also, ultrasound irradiation has been tested to improve the synthesis of PU. Under these conditions, TPUs were obtained in high yields (80–99%) with weight‐average molecular weights in the 36–83 kDa range. The chemical structures of PUs were assessed by FTIR and NMR spectroscopy. The thermal and mechanical properties of the synthesized TPUs have been studied and they showed a clear dependence on the structure of the parent diol. MTT test was carried out to asses the potential cytotoxicity of the prepared PUs, indicating no cytotoxic response. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Structure and properties of polyurethanes based on halogenated and nonhalogenated soy–polyols

Four polyols were prepared by a ring opening of epoxidized soybean oil with HCl, HBr, methanol, and by hydrogenation. Two series of polyurethanes were prepared by reacting the polyols with two commercial isocyanates: PAPI and Isonate 2143L. Generally, the properties of the two series were similar. The crosslinking density of the polyurethane networks was analyzed by swelling in toluene. Brominated polyols and their corresponding polyurethanes had the highest densities, followed by the chlorinated, methoxylated, and hydrogenated samples. The polyurethanes with brominated and chlorinated polyols had comparable glass transition and strength, somewhat higher than the polyurethane from methoxy containing polyol, while the polyurethane from the hydrogenated polyol had lower glass‐transition and mechanical properties. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4062–4069, 2000     

Novel Fluorine-Containing Anionic Aqueous Polyurethanes

Abstract

Various amounts of fluorine-containing polyol (F-diol, MW = 3700) were introduced into the soft segment of anionic aqueous polyurethanes (PUs) to examine the effect of the F-diol on the properties of the anionic aqueous PUs. The hard segments in the anionic aqueous PUs consisted of 4,4′-methylene bis(cyclohexylisocyanate), dimethylolpropionic acid, and 1,4-cyclohexanediamine (cis/trans = 80/20). Both the mechanical and water resistance properties of the anionic aqueous PUs were improved after introducing small amounts of the F-diol in the soft segment of the aqueous PUs. This is due to the increased intermolecular forces and crystallinity as well as the hydrophobic characteristic of the F-diol. Thermal analysis of the F-diol modified anionic aqueous PUs by differential scanning calorimetry and dynamic mechanical analysis indicated that both intermolecular forces and crystallinity increased with increasing concentration of the F-diol. However, both the increased intermolecular forces and crystallinity could have an adverse effect on the interface adhesion.